The principle of treatment for lumbar instability is that, if symptoms are not relieved after conservative treatment for symptoms with obvious neurological stress, it is an indication for surgical treatment. Initially, surgical treatment adopts intervertebral disc nucleus pulposus removal with spinal canal decompression, in which the nucleus pulposus and annulus fibrosis were removed by posterior incision of the intervertebral disc, thereby enlarging the spinal canal decompression and relieving the compression of the spinal cord and nerve roots. However, since the removal of the lamina destroys the structure of the spine, a new instability factor is created in the spine, and the compression of the intervertebral space is not restored, resulting in a higher recurrence rate after surgery.
Later, intervertebral disc removal with spinal fusion surgery is used, in which various methods of interbody fusion are performed on the basis of spinal canal decompression and nucleus pulposus removal, such as interspinous bone graft fusion, intertransverse bone graft fusion, bone graft together with internal fixation device fusion and so on. The purpose of this type of fusion surgery is to increase the strength of the intervertebral structure and eliminate the instability of the spine caused by laminectomy. However, the height of the intervertebral space is not restored, and the intervertebral activity disappears after fusion, resulting in accelerated degeneration of adjacent intervertebral discs. From a wide range of perspectives, the reduction of activity of a single intervertebral activity is also an “unstable” condition. Therefore, there are still many patients with postoperative bone graft loosening, fracture, absorption, and loosening and fracture of internal fixation devices.
The traditional fusion cage material is pure polyether-ether-ketone (PEEK) material or pure bone trabecular material. The singleness of the material makes the performance of the product greatly compromised. Good elastic modulus of human bone is obtained but no bone growth effect is achieved. The two cannot coexist. Therefore, the patient's postoperative recovery is slow, and the fusion effect is relatively poor. In addition, as shown in FIG. 1 and FIG. 2, the current traditional fusion cage surgery requires the implantation of two fusion cages. The operation is complicated and difficult, which leads to large and plural wounds, more bleeding, slow postoperative recovery, and relatively poor fusion effect.